问题
I'm currently creating a parser for an XML-file and everything works fine until I add an extra option to retrieve a link. I have several tags of the same name and I want one specific tag with a specific attribute value.
...
<artist>
<name>Venom</name>
<mbid>5ddddef1-fd5a-4ca8-8e89-df4adff4239b</mbid>
<url>Venom</url>
<image size="small">http://userserve-ak.last.fm/serve/34/35628151.png</image>
<image size="medium">http://userserve-ak.last.fm/serve/64/35628151.png</image>
<image size="large">http://userserve-ak.last.fm/serve/126/35628151.png</image>
<image size="extralarge">http://userserve-ak.last.fm/serve/252/35628151.png</image>
</artist>
...
I'm fishing for the link in "extralarge".
My current code:
...
private TrackInfo readTrack(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "track");
String artist = null;
String artistPic = null;
String artisMbid = null;
String song = null;
String album = null;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (name.equals("artist")) {
parser.require(XmlPullParser.START_TAG, ns, "artist");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String artistName = parser.getName();
if (artistName.equals("name")) {
artist = readArtist(parser);
} else if (artistName.equals("mbid")) {
artisMbid = readArtistMbid(parser);
} else if (artistName.equals("image")) {
artistPic = readArtistPic(parser);
} else {
skip(parser);
}
}
} else if (name.equals("name")) {
song = readSong(parser);
} else if (name.equals("album")) {
album = readAlbum(parser);
} else {
skip(parser);
}
}
return new TrackInfo(artist, artistPic, artisMbid, song, album);
}
...
private String readArtistPic(XmlPullParser parser) throws XmlPullParserException, IOException {
String artistPic = "";
parser.require(XmlPullParser.START_TAG, ns, "image");
String tag = parser.getName();
String relType = parser.getAttributeValue(null, "size");
if (tag.equals("image")) {
if (relType.equals("extralarge")) {
artistPic = readText(parser);
parser.nextTag();
}
}
parser.require(XmlPullParser.END_TAG, ns, "image");
return artistPic;
}
...
private String readText(XmlPullParser parser) throws XmlPullParserException, IOException {
String result = "";
if (parser.next() == XmlPullParser.TEXT) {
result = parser.getText();
parser.nextTag();
}
return result;
}
...
The error:
E/CurrentTrackFragment logging﹕ XmlPullParserException: org.xmlpull.v1.XmlPullParserException: expected: END_TAG {null}image (position:START_TAG <image size='small'>@10:29 in java.io.InputStreamReader@52a3a014)
Anybody any idea how to handle this?
Solution!
I started working with the example Raghunandan gave me. In the end I only simplified my code and added the 'check = true' he suggested.
private TrackInfo readTrack(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "track");
boolean nowPlaying = false;
String artist = null;
String artistPic = null;
String artistMbid = null;
String song = null;
String songUrl = null;
String album = null;
String albumPic = null;
int playedUts = 0;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (name.equals("artist")) {
parser.require(XmlPullParser.START_TAG, ns, "artist");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String artistName = parser.getName();
if (artistName.equals("name")) {
artist = readArtist(parser);
} else if (artistName.equals("mbid")) {
artistMbid = readArtistMbid(parser);
} else if (artistName.equals("image")) {
boolean check = false;
String imagesize = parser.getAttributeValue(null, "size");
if (imagesize.equals("extralarge")) {
check = true;
}
if (check) {
artistPic = readArtistPic(parser);
} else {
parser.nextText();
}
} else {
skip(parser);
}
}
} else if (name.equals("name")) {
song = readSong(parser);
} else if (name.equals("url")) {
songUrl = readSongUrl(parser);
} else if (name.equals("album")) {
album = readAlbum(parser);
} else if (name.equals("date")) {
playedUts = Integer.parseInt(readUts(parser));
} else {
skip(parser);
}
}
return new TrackInfo(nowPlaying, artist, artistPic, artistMbid, song, songUrl,
album, albumPic, playedUts);
}
...
private String readArtistPic(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "image");
String artistPic = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "image");
return artistPic;
}
...
回答1:
Without the full stacktrace its hard to point the mistake. However the below works.
public class XMLPullParserHandler {
private String text;
public XMLPullParserHandler() {
}
public Void parse(InputStream is) { // pas the input stream
XmlPullParserFactory factory = null;
XmlPullParser parser = null;
try {
factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(true);
parser = factory.newPullParser();
parser.setInput(is, null);
boolean check =false;
//factory instantiates an object
int eventType = parser.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
String tagname = parser.getName();
switch (eventType) {
case XmlPullParser.START_TAG:
if (tagname.equalsIgnoreCase("image")) {
if(parser.getAttributeValue(null, "size").equals("extralarge"))
{
check=true;
}
}
break;
case XmlPullParser.TEXT:
text = parser.getText();
break;
case XmlPullParser.END_TAG:
String val = null;
if (tagname.equalsIgnoreCase("name")) {
val=text;
Log.i(""," name is "+val);
}
else if (tagname.equalsIgnoreCase("mbid"))
{
val=text;
Log.i(""," mbid is "+val);
}
else if (tagname.equalsIgnoreCase("url"))
{
val=text;
Log.i(""," url is "+val);
}
else if (tagname.equalsIgnoreCase("image"))
{
val=text;
if(check == true)
Log.i(""," image is "+val);
}
break;
default:
break;
}
eventType = parser.next();
}
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
The log
04-24 04:39:06.906: I/(1539): name is Venom
04-24 04:39:06.906: I/(1539): mbid is 5ddddef1-fd5a-4ca8-8e89-df4adff4239b
04-24 04:39:06.916: I/(1539): url is Venom
04-24 04:39:06.916: I/(1539): name is http://userserve-ak.last.fm/serve/252/35628151.png
Alternative Solution :
private TrackInfo readTrack(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "track");
boolean nowPlaying = false;
String artist = null;
String artistPic = null;
String artistMbid = null;
String song = null;
String songUrl = null;
String album = null;
String albumPic = null;
int playedUts = 0;
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if (name.equals("artist")) {
parser.require(XmlPullParser.START_TAG, ns, "artist");
while (parser.next() != XmlPullParser.END_TAG) {
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String artistName = parser.getName();
if (artistName.equals("name")) {
artist = readArtist(parser);
} else if (artistName.equals("mbid")) {
artistMbid = readArtistMbid(parser);
} else if (artistName.equals("image")) {
boolean check = false;
String imagesize = parser.getAttributeValue(null, "size");
if (imagesize.equals("extralarge")) {
check = true;
}
if (check) {
artistPic = readArtistPic(parser);
} else {
parser.nextText();
}
} else {
skip(parser);
}
}
} else if (name.equals("name")) {
song = readSong(parser);
} else if (name.equals("url")) {
songUrl = readSongUrl(parser);
} else if (name.equals("album")) {
album = readAlbum(parser);
} else if (name.equals("date")) {
playedUts = Integer.parseInt(readUts(parser));
} else {
skip(parser);
}
}
return new TrackInfo(nowPlaying, artist, artistPic, artistMbid, song, songUrl,
album, albumPic, playedUts);
}
...
private String readArtistPic(XmlPullParser parser) throws XmlPullParserException, IOException {
parser.require(XmlPullParser.START_TAG, ns, "image");
String artistPic = readText(parser);
parser.require(XmlPullParser.END_TAG, ns, "image");
return artistPic;
}
...
来源：https://stackoverflow.com/questions/23263086/xmlpullparser-get-data-from-tag-with-specific-attributevalue